Metal complexes of azo dyes and their uses in ink-jet printing

ABSTRACT

A compound of Formula (1) or a salt thereof:  
                 
wherein: X and Y are each independently a substituent; 
     G is optionally substituted C 1-12 -alkylene; M is a metal n is 0 to 6; p is 0 to 3;    R 1  is optionally substituted C 1-8 -alkyl, optionally substituted C 5-8  cycloalkyl, optionally substituted aryl or an optionally substituted heterocycle; and    R 2  is H, or C 1-4 -alkyl; 
 
provided that R 1  is free from carboxy groups. 
Also an ink-jet printing ink, an ink-jet printing process, a printed material and an ink jet printer cartridge.

This invention relates to compounds, to compositions containing thesecompounds, to inks, to printing processes, to printed substrates and toink-jet printer cartridges.

Ink-jet printing is a non-impact printing technique in which droplets ofink are ejected through a fine nozzle onto a substrate without bringingthe nozzle into contact with the substrate.

There are many demanding performance requirements for dyes and inks usedin ink-jet printing. For example they desirably provide sharp,non-feathered images having good water, light and ozone fastness andoptical density. The inks are often required to dry-quickly when appliedto a substrate to prevent smudging, but they should not form a crustover the tip of an ink-jet nozzle because this will stop the printerfrom working. The inks should also be stable to storage over timewithout decomposing or forming a precipitate that could block the finenozzle.

Copper chelate dyes are known from, for example, U.S. Pat. No. 6,265,554B1. However, there is a continuing need to provide colorants havingsuperior properties in ink-jet printing inks.

A particular problem for photorealistic quality printing is that oflight-fastness. Prints are often exposed to daylight for long periodsand there is a need for the image to have as good light-fastness aspossible. The colorants in the print reacting with atmospheric ozone canplay a major role in the fading of the dye.

This invention relates to magenta colorants suitable for use in ink-jetprinting with improved light-fastness and to ink jet associated productsand processes using these colourants.

According to the present invention there is provided a compound ofFormula (1) or a salt thereof:

wherein:

-   X and Y are each independently a substituent;-   G is optionally substituted C₁₋₁₂-alkylene;-   M is a metal-   n is 0 to 6;-   p is 0 to 3;-   R¹ is optionally substituted C₁₋₈-alkyl, optionally substituted C₅₋₈    cycloalkyl, optionally substituted aryl or optionally substituted    heterocyclyl; and-   R² is H, or C₁₋₄-alkyl;    provided that R¹ is free from carboxy groups.

Preferably M is copper, more preferably M is Cu²⁺.

Compounds of Formula (1) may also comprise 1 or more additional ligands.These ligands may be coloured or colourless and when there is more thanone ligand they may be the same or different. For example water may be afurther ligand to M.

Preferably X and Y are each independently selected from: optionallysubstituted alkyl (preferably C₁₋₄-alkyl), optionally substitutedalkenyl (preferably C₁₋₄-alkenyl), optionally substituted alkynyl(preferably C₁₋₄-alkynyl), optionally substituted alkoxy (preferablyC₁₋₄-alkoxy), optionally substituted aryl (preferably phenyl),optionally substituted aryloxy (preferably phenoxy), optionallysubstituted heterocycyl, polyalkylene oxide (preferably polyethyleneoxide or polypropylene oxide), carboxy, phosphato, sulpho, nitro, cyano,halo, ureido, —SO₂F, hydroxy, ester, —NR³R⁴, —COR³, —CONR³R⁴, —NHCOR³,carboxyester, sulphone, and —SO₂NR³R⁴ wherein R³ and R⁴ are eachindependently H or optionally substituted alkyl (especially C₁₋₄-alkyl)or, in the case of —CONR³R⁴ and —SO₂NR³R⁴, R³ and R⁴ together with thenitrogen atom to which they are attached may represent an aliphatic oraromatic ring system. Optional substituents for any of the substituentsdescribed for X and Y may be selected from the same list ofsubstituents.

Preferably X is sulpho, hydroxy or amino.

Preferably Y is sulpho, amino, carboxy or phosphato.

G preferably is optionally substituted C₁₋₈-alkylene and more preferablyoptionally substituted C₁₋₄-alkyl, especially C₂₋₄-alkyl.

Optional substituents present on G are preferably selected from:optionally substituted alkenyl (preferably C₁₋₄-alkenyl), optionallysubstituted alkynyl (preferably C₁₋₄-alkynyl), optionally substitutedalkoxy (preferably C₁₋₄-alkoxy), optionally substituted aryl (preferablyphenyl), optionally substituted aryloxy (preferably phenoxy), optionallysubstituted heterocycyl, polyalkylene oxide (preferably polyethyleneoxide or polypropylene oxide), carboxy, phosphato, sulpho, nitro, cyano,halo, ureido, —SO₂F, hydroxy, ester, —NR³R⁴, —COR³, —CONR³R⁴, —NHCOR³,carboxyester, sulphone, and —SO₂NR³R⁴, wherein R³ and R⁴ are as definedabove. Optional substituents for any of the substituents described for Gmay be selected from the same list of substituents.

R¹ is preferably optionally substituted C₁₋₈alkyl, especiallyC₁₋₄-alkyl; optionally substituted phenyl or optionally substitutedheterocycyl.

When R¹ is optionally substituted C₁₋₈-alkyl preferred substituents areselected independently from those listed above for G. When R¹ isoptionally substituted C₁₋₈ alkyl it is especially preferred that R¹ issubstituted with one or more groups selected from the group consistingof sulpho; phosphate; hydroxy; cyano, optionally substituted phenyl,especially phenylurea; optionally substituted heterocycyl, especiallytetrahydrofuranyl.

When R¹ is optionally substituted phenyl or optionally substitutedheterocycyl preferred substituents are selected independently from thoselisted above for X and Y.

R² is preferably H or methyl.

Acid or basic groups on the compounds of Formula (1), particularly acidgroups, are preferably in the form of a salt. Thus, the Formulae shownherein include the compounds in free acid and in salt forms and inmixtures thereof.

Preferred salts are alkali metal salts, especially lithium, sodium andpotassium, ammonium and substituted ammonium salts (including quaternaryamines such as ((CH₃)₄N⁺) and mixtures thereof. Especially preferred aresalts with sodium, lithium, ammonia and volatile amines and mixturesthereof, more especially preferred salts are sodium salts. The compoundsmay be converted into salts using known techniques.

The compounds of Formula (1) may exist in tautomeric forms other thanthose shown in this specification. These tautomers are included withinthe scope of the present invention.

The metal complexes comprising compounds of Formula (1) have attractive,strong magenta shades and are valuable colorants for use in thepreparation of ink-jet printing inks. They benefit from a good balanceof solubility, storage stability and fastness to water and light. Inparticular they display excellent light and ozone fastness.

According to a second aspect of the present invention there is provideda composition comprising a compound of Formula (1) according to thefirst aspect of the invention and a medium, preferably a liquid medium.

Preferred compositions comprise:

-   -   (a) from 0.01 to 30 parts of a compound according to the first        aspect of the invention; and    -   (b) from 70 to 99.99 parts of a liquid medium.

The number of parts of component (a) is preferably from 0.1 to 20, morepreferably from 0.5 to 15, and especially from 1 to 5 parts. The numberof parts of component (b) is preferably from 99.9 to 80, more preferablyfrom 99.5 to 85, especially from 99 to 95 parts.

Preferably component (a) is completely dissolved in component (b).Preferably component (a) has a solubility in component (b) at 20° C. ofat least 10%. This allows the preparation of liquid dye concentratesthat may be used to prepare more dilute inks and reduces the chance ofthe dye precipitating if evaporation of the liquid medium occurs duringstorage.

Preferred liquid media include water, a mixture of water and organicsolvent and organic solvent free from water.

When the medium comprises a mixture of water and organic solvent, theweight ratio of water to organic solvent is preferably from 99:1 to1:99, more preferably from 99:1 to 50:50 and especially from 95:5 to80:20.

It is preferred that the organic solvent present in the mixture of waterand organic solvent is a water-miscible organic solvent or a mixture ofsuch solvents. Preferred water-miscible organic solvents includeC₁₋₆-alkanols, preferably methanol, ethanol, n-propanol, isopropanol,n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol andcyclohexanol; linear amides, preferably dimethylformamide ordimethylacetamide; ketones and ketone-alcohols, preferably acetone,methyl ether ketone, cyclohexanone and diacetone alcohol; water-miscibleethers, preferably tetrahydrofuran and dioxane; diols, preferably diolshaving from 2 to 12 carbon atoms, for example pentane-1,5-diol, ethyleneglycol, propylene glycol, butylene glycol, pentylene glycol, hexyleneglycol and thiodiglycol and oligo- and poly-alkyleneglycols, preferablydiethylene glycol, triethylene glycol, polyethylene glycol andpolypropylene glycol; triols, preferably glycerol and 1,2,6-hexanetriol;mono-C₁₋₄-alkyl ethers of diols, preferably mono-C₁₋₄-alkyl ethers ofdiols having 2 to 12 carbon atoms, especially 2-methoxyethanol,2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol,2-[2-(2-methoxyethoxy)ethoxy]ethanol,2-[2-(2-ethoxyethoxy)ethoxy]-ethanol and ethyleneglycol monoallylether;cyclic amides, preferably 2-pyrrolidone, N-methyl-2-pyrrolidone,N-ethyl-2-pyrrolidone, caprolactam and 1,3-dimethylimidazolidone; cyclicesters, preferably caprolactone; sulphoxides, preferably dimethylsulphoxide and sulpholane. Preferably the liquid medium comprises waterand 2 or more, especially from 2 to 8, water-miscible organic solvents.

Especially preferred water-miscible organic solvents are cyclic amides,especially 2-pyrrolidone, N-methyl-pyrrolidone and N-ethyl-pyrrolidone;diols, especially 1,5-pentane diol, ethyleneglycol, thiodiglycol,diethyleneglycol and triethyleneglycol; and mono- C₁₋₄-alkyl andC₁₋₄-alkyl ethers of diols, more preferably mono-C₁₋₄-alkyl ethers ofdiols having 2 to 12 carbon atoms, especially2-methoxy-2-ethoxy-2-ethoxyethanol.

Examples of further suitable liquid media comprising a mixture of waterand one or more organic solvents are described in U.S. Pat. No.4,963,189, U.S. Pat. No. 4,703,113, U.S. Pat. No. 4,626,284 and EP4,251,50A.

When the liquid medium comprises an organic solvent free from water,(i.e. less than 1% water by weight) the solvent preferably has a boilingpoint of from 30° to 200° C., more preferably of from 40° to 150° C.,especially from 50 to 125° C. The organic solvent may bewater-immiscible, water-miscible or a mixture of such solvents.Preferred water-miscible organic solvents are any of thehereinbefore-described water-miscible organic solvents and mixturesthereof. Preferred water-immiscible solvents include, for example,aliphatic hydrocarbons; esters, preferably ethyl acetate; chlorinatedhydrocarbons, preferably CH₂Cl₂; and ethers, preferably diethyl ether;and mixtures thereof.

When the liquid medium comprises a water-immiscible organic solvent,preferably a polar solvent is included because this enhances solubilityof the compound in the liquid medium. Examples of polar solvents includeC₁₋₄-alcohols.

In view of the foregoing preferences it is especially preferred thatwhere the liquid medium is an organic solvent free from water itcomprises a ketone (especially methyl ethyl ketone) and/or an alcohol(especially a C₁₋₄-alkanol, more especially ethanol or propanol).

The organic solvent free from water may be a single organic solvent or amixture of two or more organic solvents. It is preferred that when themedium is an organic solvent free from water it is a mixture of 2 to 5different organic solvents. This allows a medium to be selected thatgives good control over the drying characteristics and storage stabilityof the ink.

Liquid media comprising an organic solvent free from water areparticularly useful where fast drying times are required andparticularly when printing onto hydrophobic and non-absorbentsubstrates, for example plastics, metal and glass.

The liquid media may also contain additional components conventionallyused in ink jet printing inks, for example viscosity and surface tensionmodifiers, corrosion inhibitors, biocides, kogation reducing additivesand surfactants which may be ionic or non-ionic.

Although not usually necessary, further colorants may be added to thecomposition to modify the shade and performance properties. Examples ofsuch colorants include C.I.Direct Yellow 86, 132, 142 and 173;C.I.Direct Blue 199, and 307; C.I.Food Black 2; C.I.Direct Black 168 and195; C.I.Acid Yellow 23; and any of the dyes used in ink jet printerssold by Seiko Epson Corporation, Hewlett Packard Company, Canon Inc. &Lexmark International. Addition of such further dyes can increaseoverall solubility leading to less kogation (nozzle blockage) for theresultant ink.

Preferably the composition according to the second aspect of theinvention is an ink suitable for use in an inkjet printer or a liquiddye concentrate. Concentrates are useful as a means for transportingcolorant and so minimising costs associated with drying the dye andtransporting excess liquid.

Thus, compositions according to the second aspect of the invention arepreferably prepared using high purity ingredients and/or by purifyingthe composition after it has been prepared. Suitable purificationtechniques are well known, e.g. ultrafiltration, reverse osmosis, ionexchange and combinations thereof (either before or after they areincorporated in a composition according to the present invention). Thispurification results in the removal of substantially all of theinorganic salts and by-products resulting from its synthesis. Suchpurification assists in the preparation of a low viscosity aqueoussolution suitable for use in an ink jet printer.

Preferably the ink has a viscosity of less than 20 cP, more preferablyless than 10 cP, especially less than 5 cP, at 25° C. These lowviscosity inks are particularly well suited for application tosubstrates by means of ink jet printers.

Preferably the ink contains less than 500 ppm, more preferably less than250 ppm, especially less than 100 pm, more especially less than 10 ppmin total of divalent and trivalent metal ions (other than any divalentand trivalent metal ions bound to a component of the ink). Free divalentand trivalent metals can form insoluble complexes on storage that couldblock the ink-jet printer nozzles.

Preferably the ink has been filtered through a filter having a mean poresize below 10 μm, more preferably below 3 μm, especially below 2 μm,more especially below 1 μm. This filtration removes particulate matterthat could otherwise block the fine nozzles found in many ink-jetprinters.

Preferably the ink contains less than 500 ppm, more preferably less than250 ppm, especially less than 100 pm, more especially less than 10 ppmin total of halide ions. High levels of halide ions can causedetrimental effects such as, for example, corrosion of metal parts inthe ink-jet printer heads

A third aspect of the invention provides a process for forming an imageon a substrate comprising applying an ink according to the second aspectof the invention thereto by means of an ink jet printer.

The ink-jet printer preferably applies the ink to the substrate in theform of droplets that are ejected through a small orifice onto thesubstrate. Preferred ink-jet printers are piezoelectric ink-jet printersand thermal ink-jet printers. In thermal ink-jet printers, programmedpulses of heat are applied to the ink in a reservoir by means of aresistor adjacent to the orifice, thereby causing the ink to be ejectedfrom the orifice in the form of small droplets directed towards thesubstrate during relative movement between the substrate and theorifice. In piezoelectric ink-jet printers the oscillation of a smallcrystal causes ejection of the ink from the orifice. Alternately the inkcan be ejected by an electromechanical actuator connected to a moveablepaddle or plunger, for example as described in International PatentApplication 00/48938 and International Patent Application 00/55089.

The substrate is preferably paper, plastic, a textile, metal or glass,more preferably paper, an overhead projector slide or a textilematerial, especially paper.

Preferred papers are plain or treated papers which may have an acid,alkaline or neutral character.

Photographic ink-jet paper is an especially preferred substrate

A fourth aspect of the present invention provides paper, plastic, atextile, metal or glass or an overhead projector slide especially papermore especially plain, coated or treated papers printed with acomposition according to the second aspect of the invention, a compoundaccording to the first aspect of the invention or by means of a processaccording to third aspect of the invention.

It is especially preferred that the fourth aspect of the presentinvention is a photographic print on photographic quality ink-jet paper.

A fifth aspect of the present invention provides an ink jet printercartridge comprising a chamber and an ink wherein the ink is in thechamber and the ink is as defined in the second aspect of the presentinvention.

The invention is further illustrated by the following Examples in whichall parts and percentages are by weight unless otherwise stated.

EXAMPLE 1

Taurine (7.8 g, 0.062 mol) was added to a solution of Reactive Red 23(Duasyn™ Red 3B-SF-VP 346 from Clariant) (25 g, 0.031 mol) in water (300ml). The reaction mixture was adjusted to pH 9 by the addition of 2NNaOH and stirred at 60° C. for 2 hours. The reaction mixture was thencooled to room temperature, the pH adjusted to 3 with concentrated HCland the product precipitated by the addition of sodium chloride. Theproduct was collected by filtration and dissolved in water (300 ml) andthe pH adjusted to pH 7 with 48% NaOH. This solution was dialysed untilthe conductivity was less than 100 μs and then evaporated in an oven at70° C. to give 19 g of a magenta solid.

EXAMPLES 2 to 4

Examples 2 to 4 were prepared using an analogous process to thatdescribed in Example 1 except that in place of taurine the aminocompounds shown in Table 1 were used to give compounds of generalFormula (2) bearing the different X substituents shown in Table 1. TABLE1 Formula (2)

Example Amino Compound X 2

3

4

COMPARATIVE EXAMPLE 1

Comparative Example 1 was prepared using an analogous process to thatdescribed in Example 1 except that the amino compound:

was used in place of taurine to give a compound of Formula (2) wherein Xis:

EXAMPLE 5

Preparation of Inks 1 to 4 and Comparative Ink 1

Inks 1 to 4 were prepared by dissolving the corresponding compounds ofExamples 1 to 4 (3.5 g) in 100 ml of a liquid medium consisting of2-pyrrolidone/thiodiglycol/Surfynol™ 465 in a weight ratio of 5:5:1.

Comparative Ink 1 was prepared by dissolving the compound of ComparativeExample 1 (3.5 g) in 100 ml of a liquid medium consisting of2-pyrrolidone/thiodiglycol/Surfynol™ 465 in a weight ratio of 5:5:1.

EXAMPLE 6

Ink-Jet Printing

Inks 1 to 4 and Comparative Ink 1 were ink-jet printed onto a variety ofpapers using a Hewlett Packard DeskJet 550C™. The CIE colourco-ordinates of each print (a, b, L, Chroma “C” and hue “h”) weremeasured using a Xrite 983™ Spectrodensitometer with 0°/45° measuringgeometry with a spectral range of 400-700 nm at 20 nm spectralintervals, using illuminant C with a 2° (CIE 1931) observer angle and adensity operation of status T. No less than 2 measurements were takendiagonally across a solid colour block on the print with a size greaterthan 10 mm×10 mm. The properties of the resultant prints of inks 1 to 4are shown in Table 2. TABLE 2 Ink Jet Print Properties % Ink Paper DepthL a b C h Ink 1 Canon PR101 ™ 100 49 65 −2 65 358 Ink 1 Canon PR101 ™ 5063 53 −7 54 352 Ink 1 Kodak 100 45 60 −3 60 357 Premium ™ Ink 1 Kodak 5057 57 −10 58 350 Premium ™ Ink 2 Canon PR101 ™ 100 45 66 −13 67 349 Ink2 Canon PR101 ™ 50 60 55 −15 57 344 Ink 2 Kodak 100 42 59 −9 60 351Premium ™ Ink 2 Kodak 50 54 58 −15 60 346 Premium ™ Ink 3 Canon PR101 ™100 51 67 3 67 3 Ink 3 Canon PR101 ™ 50 64 55 −6 56 354 Ink 3 Kodak 10046 61 1 61 1 Premium ™ Ink 3 Kodak 50 58 57 −7 57 353 Premium ™ Ink 4Canon PR101 ™ 100 47 68 3 68 2 Ink 4 Canon PR101 ™ 50 60 60 −6 61 355Ink 4 Kodak 100 39 49 −10 50 349 Premium ™ Ink 4 Kodak 50 53 51 −13 53346 Premium ™Light Fastness

To evaluate light fastness the prints were irradiated in an Atlas Ci35Weatherometer for 100 hours. The results are shown in Table 3 wheredegree of fade is expressed as ΔE where a lower figure indicates higherlight fastness. ΔE is defined as the overall change in the CIE colourco-ordinates L*, a*, b* of the print and is expressed by the equationΔE=(ΔL²+Δa²+Δb²)^(0.5). TABLE 3 Light Fastness Ink Paper ΔE Ink 1 CanonPR101 ™ 4 Ink 1 Kodak Premium ™ 6 Ink 2 Canon PR101 ™ 7 Ink 2 KodakPremium ™ 9 Ink 3 Canon PR101 ™ 9 Ink 3 Kodak Premium ™ 10 Ink 4 CanonPR101 ™ 10 Ink 4 Kodak Premium ™ 12 Comparative Ink Canon PR101 ™ 15Comparative Ink Kodak Premium ™ 14

From Table 3 it is clear that the inks of the present invention displayan unexpected superior light fastness to those inks wherein R¹ containsa carboxy group.

Further Inks

The inks described in Tables A and B may be prepared wherein the Dyedescribed in the first column is the compound made in the above Exampleof the same number. Numbers quoted in the second column onwards refer tothe number of parts of the relevant ingredient and all parts are byweight. The inks may be applied to paper by ink-jet printing.

The following abbreviations are used in Tables A and B:

-   -   PG=propylene glycol    -   DEG=diethylene glycol    -   NMP=N-methylpyrollidone    -   DMK=dimethylketone    -   IPA=isopropanol    -   MEOH=methanol    -   2P=2-pyrrolidone    -   MIBK=methylisobutyl ketone    -   P12=propane-1,2-diol    -   BDL=butane-2,3-diol    -   CET=cetyl ammonium bromide    -   PHO=Na₂HPO₄ and    -   TBT=tertiary butanol

TDG=thiodiglycol TABLE A Dye of Dye Na Example Content Water PG DEG NMPDMK NaOH Stearate IPA MEOH 2P MIBK 1 2.0 80 5 6 4 5 2 3.0 90 5 5 0.2 310.0 85 3 3 3 5 1 4 2.1 91 8 1 1 3.1 86 5 0.2 4 5 1 1.1 81 9 0.5 0.5 9 22.5 60 4 15 3 3 6 10 5 4 3 5 65 20 10 4 2.4 75 5 4 5 6 5 1 4.1 80 3 5 210 0.3 1 3.2 65 5 4 6 5 4 6 5 2 5.1 96 4 1 10.8 90 5 5 2 10.0 80 2 6 2 51 4 3 1.8 80 5 15 4 2.6 84 11 5 1 3.3 80 2 10 2 6 1 12.0 90 7 0.3 3 15.4 69 2 20 2 1 3 3 1 6.0 91 4 5

TABLE B Dye of Dye Example Content Water PG DEG NMP CET TBT TDG BDL PHO2P PI2 1 3.0 80 15 0.2 5 2 9.0 90 5 1.2 5 3 1.5 85 5 5 0.15 5.0 0.2 42.5 90 6 4 0.12 1 3.1 82 4 8 0.3 6 1 0.9 85 10 5 0.2 2 8.0 90 5 5 0.3 34.0 70 10 4 1 4 11 4 2.2 75 4 10 3 2 6 1 10.0 91 6 3 1 9.0 76 9 7 3.00.95 5 1 5.0 78 5 11 6 2 5.4 86 7 7 3 2.1 70 5 5 5 0.1 0.2 0.1 5 0.1 5 42.0 90 10 1 2 88 10 1 5 78 5 12 5 1 8 70 2 8 15 5 1 10 80 8 12 1 10 8010

1. A compound of Formula (1) or a salt thereof:

wherein: X and Y are each independently a substituent; G is optionallysubstituted C₁₋₁₂-alkylene; M is a metal n is 0 to 6; p is 0 to 3; R¹ isoptionally substituted C₁₋₈-alkyl, optionally substituted C₅₋₈cycloalkyl, optionally substituted aryl or an optionally substitutedheterocycle; and R² is H, or C₁₋₄-alkyl; provided that R¹ is free fromcarboxy groups.
 2. A compound according to claim 1 wherein M is Cu²⁺. 3.A compound according to either claim 1 or claim 2 wherein G isoptionally substituted C₁₋₄-alkyl.
 4. A compound according to eitherclaim 1 or claim 2 wherein R¹ is optionally substituted C₁₋₈-alkyl,optionally substituted phenyl or an optionally substituted heterocycyl.5. A compound according to either claim 1 or claim 2 wherein R² is H ormethyl.
 6. A composition comprising a compound as described in claim 1and a liquid medium.
 7. A composition according to claim 6 which is anink suitable for use in an ink jet printer.
 8. A process for forming animage on a substrate which comprises applying an ink as described inclaim 7 thereto by means of an ink jet printer.
 9. A paper, a plastic, atextile, metal or glass, or an overhead projector slide printed with acompound as described in claim
 1. 10. An ink jet printer cartridgecomprising a chamber and an ink wherein the ink is in the chamber andthe ink is as defined in claim 7.